(125a) Dynamic Analysis for Piston-Type Work Exchanger and Network Design for Mechanical Energy Recovery

The fundamental concept of work exchanger network (WEN) and basic system analysis were first introduced by Huang and Fan in 1996. [1] Today, WEN design for mechanical energy recovery has become an active area of research in process systems engineering. [2] The process units used for WEN are of two types: the flow work exchanger which can be called the direct work exchanger, and the compressor-turbine type which can be termed indirect work exchanger. Amini-Rankouhi and Huang developed a thermodynamic modeling based method for predicting the maximum amount of recoverable mechanical energy prior to WEN synthesis, and reported a basic analysis for the design of a direct work exchanger. [3],[4]

In this paper, we extend our research on piston-type direct work exchanger to the dynamic domain and on the dynamic-behavior-incorporated WEN design. In dynamic study, CFD simulation is performed to reveal the dynamic behavior in the pressurization-depressurization cycle under different operational scenarios, such as in adiabatic, isothermal, and non-isothermal conditions within a direct work exchanger. In simulation, thermal behavior of process streams is also observed, which provides critical information for unit design. The dynamic characterization of work exchanger is incorporated in the thermodynamic-model-based heat-integrated WEN design. We will show how mechanical energy can be cost effectively recovered in a direct work exchanger based network as compared with those using other types of work exchangers. We will also discuss a number of factors for operational stability and safety in WEN.

References

[1] Huang, Y. L. and L. T. Fan, "Analysis of Work Exchanger Networks," Industrial & Engineering Chemistry Research, 35, 3528-3538, 1996.

[2] Yu, H., C. Fu, and T. Gundersen, “Work Exchange Networks (WENs) and Work and Heat Exchange Networks (WHENs): A Review of the Current State of the Art,” Industrial & Engineering Chemistry Research, 59, 507-525, 2020.

[3] Amini-Rankouhi, A. and Y. Huang, "Prediction of Maximum Recoverable Mechanical Energy via Work Integration: A Thermodynamic Modeling and Analysis Approach," 63(11), 4814-4826, 2017.

[4] Amini-Rankouhi, A. and Y. Huang, “Modeling and Simulation of a Piston-Type Work Exchanger for Mechanical Energy Recovery,” Industrial & Engineering Chemistry Research, 58(39), 18292-18300, 2019.